It describes a design technique to facilitate testing of GUIs, which involves keeping all logic out of the dialog box, but instead putting it in a non-GUI class that essentially has a one-to-one mapping of typical view functions. You can then easily create a mock view to guarantee the contract between this class and the view, and then finally create "The Humble Dialog Box". As stated in the paper, "Notice that each [dialog box] action method is very small, just a simple delegation. Every method that receives data on the view is as close to a pure �set� method as possible."